System for retaining an upper on a sole structure

ABSTRACT

An article of footwear, comprising a sole having a top portion and a bottom portion, and one or more straps, wherein at least one of the straps extends from the top portion to the bottom portion through a channel in the sole, and the strap has a plug end; and a retention element disposed between the plug end and the bottom portion of the sole, wherein the retention element comprises a base and one or more flanges disposed at an outer edge of the base projecting angularly upward and away from the base.

BACKGROUND

The inventive subject matter is generally directed to system for securing an upper on a sole structure for an article of footwear, and particularly a type of sandal known as thongs or flip-flops. More particularly, it is directed to a thong sandal having at least one strap attached to a sole structure of the sandal, and the strap has a retention element that helps prevents the strap from being pulled out of the sole structure when an upward tension is applied to the strap.

Thong sandals are a very popular type of footwear, and they may be preferred over other types of sandals for their simple design, ease of use, and comfort. A thong sandal typically includes an upper and a sole structure, wherein the sole structure is typically made of one or more layers of a foamed rubber material, unfoamed rubber, natural or synthetic leather, or a combination of such materials. The upper can include one or more straps attached to the sole structure. The sandal is held on a wearer's foot by the straps passing over the top or around the sides of the foot. The straps, which can be formed from a variety of materials (e.g., textiles, plastic, leather, synthetic leather, etc.) typically include a toe post or thong that fits between the first and second toes of a wearer. A generally “Y” shaped upper can be formed by joining the toe post with a pair of flexible straps, which respectively connect to the lateral and medial sides of the sole structure near the middle or rear region of sandal.

However, one disadvantage of the thong sandal is that under force the straps may become dislodged from the sole structure, particularly as the sole structure wears thin. This problem is particularly common for the toe post, which is frequently under upward lifting tension during activities (e.g., walking, running, etc.). As a result, the straps may be pulled out of the sole structure.

Previous attempts at solving one or more of the aforementioned problems have been made. For example, U.S. Pat. Nos. 9,259,048, 7,540,098, U.S. Publication No. 2009/0044423, and AU Patent No. 2013100142 disclose various mechanisms to help secure a toe post to a sandal's sole. The foregoing patent documents are hereby incorporated by reference in their entireties for all purposes. However, these methods have a number of shortcomings, including but are not limited to, inadequate protection, design complexity, and so on.

Therefore, there is a need for an improved system for retaining uppers on sole structures. There is particularly a need for an improved thong sandal that can be easily constructed, and effectively resist external tension so as to help prevent the straps from being pulled out of the sole structure.

SUMMARY

The innovations disclosed herein overcome problems in the prior art and address one or more of the aforementioned or other needs.

In some respects, the innovations disclosed here are generally directed to improved systems for retaining uppers on sole structures.

In some respects, the innovations disclosed herein are generally directed to an improved strap system for a sandal. According to some embodiments, the strap system includes a strap and a retention element. The strap can pass through a channel across a sole of the sandal, and the strap can have a plug end. The retention element can be disposed between the plug end and a bottom portion of the sole. The retention element can also include a base and one or more flanges disposed at an outer edge of the base projecting angularly upward and away from the base.

In some embodiments, the channel can terminate to a recess at the bottom portion of the sole. The retention element can be configured to engage with the sole by an interface between the flanges and an area surrounding a bottom opening of the channel in the recess when an upward tension is applied to the strap.

In some embodiments, the base has a generally planar surface. In certain embodiments, the base can have an aperture configured to allow the strap to pass through. The base can have a gap extending from the outer edge to the aperture, and the retention element can be configured to allow the strap to pass through the gap into the aperture.

In certain embodiments, the strap can be a toe post positioned at a front region of the sole. In certain embodiments, the strap can be positioned at a medial side or a lateral side of the sole. In the foregoing and other embodiments, the base and any of the flanges can form an angle between 20 degrees and 70 degrees. In certain embodiments, the angle is about 45 degrees.

According to some embodiments, the flanges can be made of a resiliently deformable material. Accordingly, the flanges can expand outwardly toward a plane that is tangent to the base when the flanges are urged against the area surrounding the bottom opening of the channel. In some other embodiments, the flanges can be made of a rigid material. According to certain embodiments, the retention element can be integrated with the strap in a unitary structure.

According to some embodiments, a widest width of the bottom opening of the channel is smaller than a distance between two opposing points on a peripheral edge of flanges. In some embodiments, any of the flanges can include one or more barbs on a peripheral edge of the flanges.

The inventive subject matter is also directed to an improved article of footwear. According to some embodiments, the article of footwear includes a sole which has a top portion and a bottom portion, as well as one or more straps. At least one of the straps can extend from the top portion to the bottom portion through a channel in the sole. The strap can have a plug end and a retention element. The retention element can be disposed between the plug end and the bottom portion of the sole. As well, the retention element can include a base and one or more flanges disposed at an outer edge of the base projecting angularly upward and away from the base.

In some embodiments, the channel can terminate to a recess at the bottom portion of the sole. The retention element can be configured to engage with the sole by an interference between the flanges and an area surrounding a bottom opening of the channel in the recess when an upward tension is applied to the strap.

In some embodiments, the base can have a generally planar surface. In certain embodiments, the base can have an aperture configured to allow the strap to pass through. The base can have a gap extending from the outer edge to the aperture, and the retention element can be configured to allow the strap to pass through the gap into the aperture.

In certain embodiments, the strap can be a toe post positioned at a front region of the sole. In certain embodiments, the strap can be positioned at a medial side or a lateral side of the sole. In the foregoing and other embodiments, the base and any of the flanges can form an angle between 20 degrees and 70 degrees. In certain embodiments, the angle is about 45 degrees.

According to some embodiments, the flanges can be made of a resiliently deformable material. Accordingly, the flanges can expand outwardly toward a plane that is tangent to the base when the flanges are urged against the area surrounding the bottom opening of the channel. In some other embodiments, the flanges can be made of a rigid material. According to certain embodiments, the retention element can be integrated with the strap in a unitary structure.

According to some embodiments, a widest width of the bottom opening of the channel is smaller than a distance between two opposing points on a peripheral edge of flanges. In certain embodiments, any of the flanges can include one or more barbs on a peripheral edge of the flange.

Related methods for constructing an article of footwear are also disclosed. For example, the methods include the acts of preparing a sole and attaching one or more straps to the sole. The sole can have a top portion and a bottom portion. At least one of the straps can extend from the top portion to the bottom portion through a channel in the sole. The strap can have a plug end and a retention element. The retention element can be disposed between the plug end and the bottom portion of the sole. As well, the retention element can include a base and one or more flanges disposed at an outer edge of the base projecting angularly upward and away from the base.

These and other embodiments are described in more detail in the following Detailed Description and the Figures. Other embodiments are contemplated in the Detailed Description below and in the appended Figures, and in the claims, as originally written or amended, the claims as such being incorporated by reference into this Summary.

The foregoing is not intended to be an exhaustive list of embodiments and features of the inventive subject matter. Persons skilled in the art are capable of appreciating other embodiments and features from the following detailed description in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The appended figures show embodiments according to the inventive subject matter, unless noted as showing prior art.

FIG. 1A shows a top perspective view of a thong sandal according to one embodiment of the inventive subject matter.

FIG. 1B shows a bottom view of the thong sandal illustrated in FIG. 1A.

FIG. 2A shows a top perspective view of a thong sandal according to another embodiment of the inventive subject matter.

FIG. 2B shows a bottom view of the thong sandal illustrated in FIG. 2A.

FIG. 3 shows the bottom view of a portion of a sandal's sole and a toe post passing through the sole.

FIG. 4 shows a top perspective view of a retention element.

FIG. 5A illustrates a top view of a retention element disposed in a recess.

FIG. 5B illustrates a cross-sectional view of the retention element shown in FIG. 5A together with a plug end of a toe post, disposed in a recess at the bottom portion of a sole.

FIG. 6 shows a top view of a retention element having a base, four flanges and a gap in the base.

FIG. 7 shows a top view of a retention element having a base, three flanges and a gap in the base.

FIG. 8 shows a top view of a retention element having a base, two flanges and a gap in the base.

FIG. 9 shows a top view of a retention element having a base, one flange and a gap in the base.

FIG. 10A shows a cross-sectional view of the retention element shown in FIG. 6 according to one embodiment.

FIG. 10B shows the cross-section view of the retention element shown in FIG. 10A when an upward tension is applied to a toe strap passing through the retention element.

FIG. 11A shows a cross-sectional view of the retention element shown in FIG. 6 according to another embodiment.

FIG. 11B shows the cross-section view of the retention element shown in FIG. 11A when an upward tension is applied to a toe strap passing through the retention element.

FIG. 12A shows a cross-sectional view of the retention element shown in FIG. 6 according to a third embodiment.

FIG. 12B shows the cross-section view of the retention element shown in FIG. 12A when an upward tension is applied to a toe strap passing through the retention element.

FIG. 13 shows a top view of a retention element having a base, four flanges, wherein each flange has a number of barbs on a peripheral edge of the flange.

FIG. 14 shows a top view of a retention element having a base and four flanges, but has no gap in the base.

FIG. 15 shows a side view of a toe post with an integrated plug end and retention element according to one embodiment of the inventive subject matter.

FIG. 16 shows a side view of a toe post with an integrated plug end and retention element according to an alternative embodiment of the inventive subject matter.

DETAILED DESCRIPTION

Representative embodiments according to the inventive subject matter are shown in FIGS. 1-16.

In some respects, the inventive subject matter is directed to an improved system for retaining an upper on a sole structure for an article of footwear. In a representative, non-limiting embodiment, the article of footwear is a thong sandal, which is a type of open-toed sandal. A thong sandal may or may not have a heel and/or heel strap. In some respects, the inventive subject matter is also directed to a toe post system for a thong sandal. Yet in other respects, the inventive subject matter is directed to a method of constructing an improved retention system for retaining an upper structure on an article of footwear. It is particularly suitable for retaining straps on a sole structure, especially a toe post on the sole structure for a thong sandal.

According to some embodiments, the thong sandal includes a sole and one or more straps. The sole structure can be made from any known or to be discovered material or materials, including one or more layers of a foamed rubber material, unfoamed rubber, natural or synthetic leather, or a combination of such materials. A popular material for thong sandals is ethylene-vinyl acetate (EVA). EVA is a polymer that approaches elastomeric materials in softness and flexibility, yet can be processed like other thermoplastics, thus providing for use of well-known injection and other molding and production techniques. The straps, which form part of an upper for the sandal, can be made with a variety of materials, such as molded rubber, plastic, leather, foam, fabric, etc. In certain embodiments, at least one of the straps is a toe post positioned at a front region of the sole. In certain embodiments, at least one of the straps is positioned at a medial side or a lateral side of the sole.

For example, FIG. 1A and FIG. 1B show a thong sandal 10 having a sole 19 and a plurality of straps (15, 15 a, 15 b). The sole 19 has a top portion 17 and a bottom portion 11. The sole 19 can be held loosely on the foot by a Y-shaped strap system including a thong strap (or toe post) 15 connecting to a front region 12 of the sole 19, a medial strap 15 a connecting to a medial portion 14 of the sole 19, and a lateral strap 15 b connecting to a lateral portion 16 of the sole 19. The straps (15, 15 a, and 15 b) can be separate pieces that are coupled together, or can be constructed in a unitary piece. The toe post 15, which passes between the first and second toes, can extend from the top portion 17 to the bottom portion 11 through a channel 13 in the sole 19. The medial and lateral straps 15 a, 15 b can also extend from the top portion 17 to the bottom portion 11 through respective channels 13 a, 13 b.

FIG. 2A and FIG. 2B show another embodiment of a thong sandal 20 including a sole 29 and a plurality of straps (25, 25 a, 25 b). A toe post 25 is connected to a front region 22 of the sole 29, extending from a top portion 27 to a bottom portion 21 through a channel 23 in the sole 29. Unlike the embodiment shown in FIGS. 1A-1B, the medial strap 25 a and lateral strap 25 b do not connect to the sole 29 via channels. Instead, the medial strap 25 a is connected to a medial side 24 of the sole 29 at an attachment point 23 a, and the lateral strap 25 b is connected to a lateral side 26 of the sole 29 at an attachment point 23 b. The connection of the medial and lateral straps 25 a, 25 b to the respective attachment points 23 a, 23 b can be implemented by gluing, screwing, buttoning, clasping, Velcro, or any known or to be discovered coupling mechanisms.

In a representative, non-limiting embodiment, a strap extending from a top portion to a bottom portion through a channel in the sole can be securely attached to the sole by a plug end and a retention element. By way of illustration and without any limitation, a toe post will be used hereafter to illustrate principals of the inventive subject matter. It should be understood that similar retention mechanism can also be applied to securely attach other straps (e.g., the medial strap and/or lateral strap) to a sandal's sole. Further, although the channels 13, 13A, 13B are shown running completely through the top to bottom of the sole, persons skilled in the art will appreciate that a strap plug end can be captured between layers of material in a sole so as not be exposed on the bottom side of the sole.

As an example of a typical toe post system, as improved by the inventive subject matter, FIG. 3 shows the bottom view of a toe post 35 passing through a front region of a sole 31. The toe post 35 can include a thong strap 36 passing through a channel 33 in the sole 31, a plug end 37 and a retention element 30. The retention element 30, which will be described more fully in the following, can be disposed between the plug end 37 and the bottom portion of the sole 31.

Attachment of the toe post 35 to the sole 31 can be accomplished by inserting the toe post's plug end 37 through the channel 33 in the sole 31 in a downward direction. Due to the deformable nature of the sole 31 and the plug end 37, the widest width of the channel 33 can be smaller than the cross-sectional width of the plug end 37. After the plug end 37 is passed through the channel 33 in the sole 31, the retention element 30 can be inserted between the plug end 37 and the bottom portion of the sole 31. The toe post 35 can also be attached to the sole 31 by inserting the thong strap 36 through the channel 33 in the sole 31 in an upward direction, thus leaving the plug end 37 at the bottom portion of the sole 31. Then the retention element 30 can be inserted between the plug end 37 and the bottom portion of the sole 31.

The width of channel 33 can be generally configured to match the width of the thong strap 36, but the channel 33 can flare to a wider bottom opening to form a recess near the bottom portion of the sole. As described more fully below, the recess can be configured to receive the plug end 37 and the retention element 30. Thus, when the toe post 35 is pulled upwards, the plug end 37 and the retention elements 30 are urged against (i.e., interference fit) the area surrounding the bottom opening of the channel 33 in the recess. The plug end 37 and the retention element 30 are retained because of the interference fit, thus helping prevent the toe post 35 from being pulled out of the sole 31.

FIG. 4 shows a three-dimensional (3D) top perspective view of a representative, but non-limiting embodiment of a retention element 40. In this example, the retention element 40 includes a base 49 and four flanges (41 a, 41 b, 41 c, and 41 d) disposed at an outer edge 42 of the base 49. The flanges (41 a, 41 b, 41 c, and 41 d) can be arranged to project angularly upward and away from the base (i.e., the flanges protrude outward of the outer edge 42 and form a certain angle with the base 49). When coupled with a strap (e.g., a toe post) passing through a sole (not shown), the flanges are arranged to project generally toward a bottom surface of the sole. For example, in FIG. 3, the flanges project toward bottom portion of the sole 31. In other embodiments (not illustrated), the plug and retention element can be sandwiched in sole material, with the flanges projecting upwardly towards the bottom surface of an intermediate layer of sole structure where a channel terminates.

In a representative, non-limiting embodiment, the base 49 can have a generally planar surface. In some embodiments, the base 49 can have an aperture 46 configured to allow a corresponding strap (not shown) to pass through. In an exemplary embodiment, the base 49 can have a gap 48 extending from the outer edge 42 to the aperture 46 in the base 49, and the retention element 40 can be configured to allow a corresponding strap (not shown) to pass through the gap 48 into the aperture 46 in the base 49.

FIG. 5A illustrates a top view of a retention element 50 disposed in a recess 53 which is disposed in a bottom surface of the sole structure. For purposes of clarity, the toe post is not shown together with the retention element 50 in FIG. 5A. FIG. 5B illustrates a cross-sectional view of the retention element 50 shown in FIG. 5A together with a toe post 55 having a thong strap 55 a and a plug end 55 b, wherein the plug end 55 b and the retention element 50 are disposed in the recess 53 at the bottom surface 57 b of the sole 57.

The cross section of the thong strap 55 a can have a circular, eclipse, rectangular, hexagonal, or any other shape. The widest width measured in the cross section of the thong strap 55 a can be labeled as Ds (i.e., Ds is the diameter of the cross section if the thong strap 55 a has a generally cylinder shape). The plug end 55 b is disposed at the distal end of the thong strap 55 a, and its top and bottom surfaces can have a circular, eclipse, rectangular, hexagonal, or any other shape. The widest width measured across the top and bottom surfaces of the plug end 55 b can be labelled as Dp (i.e., Dp is the diameter of the surface if the plug end 55 b has a generally circular shape). Dp is greater than Ds to allow the plug end 55 b in combination with the retention element 50 to engage the sole structure 57 in an interference fit.

Similar to the example shown in FIG. 4, the retention element 50 has a base 59 and four flanges (51 a, 51 b, 51 c, and 51 d) disposed at an outer edge 52 of the base 59 projecting angularly upward and away from the base 59. Similarly, the base 59 can also have an aperture 56, and a gap 58 extending from the outer edge 52 to the aperture 56. The widest width Db of the aperture 56 (e.g., Db is the diameter of the aperture 56 if the aperture 56 has a circular shape) is generally larger than Ds (i.e., the widest width of the cross section of the thong strap 55 a). The size of the gap 58 can be smaller than Ds. But since the thong strap 55 a can be made of flexible materials and be deformable, the thong strap 55 a can be squeezed though the gap 58 and into the aperture 56.

Channel 54 starts at the top surface 57 a of the sole 47 and terminates to a widened recess 53 at the bottom surface 57 b of the sole 57, for receiving the plug end 55 b and the retention element 50. The region of the recess 53 can be confined by an outer boundary 53 a. One or both of the plug end 55 b and the retention element 50 can match the geometric shape of the recess 53. For example, the widest width of the recess Dr (e.g., Dr is the diameter of the recess 53 if the recess 53 has a circular shape) can be similar to, or slightly larger than Dp (i.e. the widest width measured across the top and bottom surfaces of the plug end 55 b). The depth of the recess 53 can be similar to, or slightly greater than the height of the plug end 55 b plus the height of the base 59 of the retention element 50. Thus, when the toe post 55 is drawn upwards, the plug end 55 b, as well as the retention element 50, can be pulled into the recess 53, and the plug end 55 b can form a flush fit or generally smooth bottom surface of the thong sandal.

The toe post 55 passes through the sole 57 via the channel 54, whose bottom opening 53 b is disposed in the recess 53. The cross section of the channel 54 may vary in size along its path. At least the widest width Da of the channel's bottom opening 53 b (e.g., Da is the diameter of the bottom opening 53 b if the channel 54 has a generally cylinder shape) is smaller than a distance De between two opposing points on a peripheral edge of the flanges. In some embodiments, when the retention element 50 is placed into the recess 53, the base 59 of the retention element 50 generally covers the bottom opening 53 b of the channel 54. According to a representative, non-limiting embodiment, the size of the plug end 55 b is generally bigger than the aperture 56 in the retention element 50, so that the plug end 55 b has an interference fit against the retention element 50. In addition, the size of the retention element 50 is generally bigger than the bottom opening 53 b of the channel 54. Thus, at least the retention element 50 can be configured to engage with the sole 57 by an interference fit between the flanges (51 a, 51 b, 51 c, and 51 d) and an area 53 c surrounding the bottom opening 53 b in the recess 53 (i.e., the area between the outer boundary 53 a and the bottom opening 53 b) when an upward tension is applied to a toe post having the retention element 50. Accordingly, it will be difficult to pull the retention element 50 and the strap's plug end 55 b away from the sole 57 through the channel 54.

The retention element can have a variety of designs. For example, the number of flanges, the space between two adjacent flanges, the size and shape of the flanges, the size and shape of the base, the size and shape of the aperture in the base, the size and shape of the gap in the base (or no gap in the base), and/or other structural features of the retention element can be varied to achieve specific functional properties and/or ornamental characteristics.

As an example, FIG. 6 shows a top view of a retention element 60 that has similar design as those shown in FIG. 4 and FIG. 5B. As illustrated in FIG. 6, the retention element 60 has a base 69 and four flanges (61 a, 61 b, 61 c and 61 d) disposed at an outer edge 62 of the base 69 projecting angularly and away from the base. Similarly, the base 69 can also have an aperture 66, and a gap 68 extending from the outer edge 62 to the aperture 66. The flanges (61 a, 61 b, 61 c and 61 d) can be disposed symmetrically, or asymmetrically along the outer edge 62. Any of the flanges can have a variety of shapes and/or sizes, and the space between two adjacent flanges can also vary.

In another example, FIG. 7 shows a top view of a retention element 70 having a base 79 and three flanges (71 a, 71 b and 71 c) disposed at an outer edge 72 of the base 79 projecting angularly and away from the base. Similarly, the base 79 can also have an aperture 76, and a gap 78 extending from the outer edge 72 to the aperture 76. The flanges (71 a, 71 b and 71 c) can be disposed symmetrically, or asymmetrically along the outer edge 72. Any of the flanges can have a variety of shapes and/or sizes, and the space between two adjacent flanges can also vary.

In an alternative example, FIG. 8 shows a top view of a retention element 80 having a base 89 and two flanges (81 a and 81 b) disposed at an outer edge 82 of the base 89 projecting angularly and away from the base. Similarly, the base 89 can also have an aperture 86, and a gap 88 extending from the outer edge 82 to the aperture 86. The flanges (81 a and 81 b) can be disposed symmetrically, or asymmetrically along the outer edge 82. Any of the flanges can have a variety of shapes and/or sizes, and the space between the two flanges can also vary.

Yet in a further example, FIG. 9 shows a top view of a retention element 90 having a base 99 and only one flange 91 disposed at an outer edge 92 of the base 99 projecting angularly and away from the base. Similarly, the base 99 can also have an aperture 96, and a gap 98 extending from the outer edge 92 to the aperture 96. The flange 91 can be disposed continuously along, or only a portion of the outer edge 82. The flange 91 can also have a variety of shapes and/or sizes.

FIG. 10A shows a cross-sectional view of the retention element shown in FIG. 6 (along line B-B′) according to one exemplary embodiment. As shown, the retention element 100 has a base 109 and one or more flanges 101. The base 109, which has an aperture 106, is generally planar, i.e., the base 109 is generally parallel to the plane 103. The flanges 101, which are disposed at the outer edge 102 of the base 109, project angularly upward and away from the base 109, when no tension is applied. For example, the flange 101 can have a tangential plane 104A, which forms an angle α with the plane 103. In a representative, non-limiting embodiment, the angle α is between about 20 degrees and about 70 degrees. In an exemplary embodiment, the angle is about 45 degrees, which can range between about 35 degrees and about 55 degrees.

According to some embodiments, the flanges 101 are made of a resiliently deformable material. FIG. 10B shows the cross-section view of the retention element 100 shown in FIG. 10A when an upward tension is applied to a toe strap (not shown) passing through the retention element 100. The tension force can be transferred to the retention element 100 coupled to the toe strap when the retention element 100 is urged against a bottom portion of the sole (not shown). Accordingly, the flanges 101 can expand outwardly toward the plane 103 that is tangent to the base 109 when the flanges 101 are urged against the bottom portion of the sole. Thus, the plane 104B of the expanded flange 101 can be pressed toward the base 109, and the angle α′ between the plane 104B and the base plane 103 is reduced compared to the original angle α. Yet according to an alternative embodiment, the flanges 101 can be made of a rigid material. When the flanges 101 are urged against the bottom portion of the sole, the flanges 101 do not deform and retain its original shape and orientation with respect to the base 109. Since the sole is typically made of foamed rubber material, the flanges 101 can piece into and grip the sole. As the flanges 101, either being made of deformable or rigid material, are pressed against the bottom portion of the sole, the associated toe post can be securely attached to the sole.

FIG. 11A shows a cross-sectional view of the retention element shown in FIG. 6 (along line B-B′) according to another embodiment. As shown, the retention element 110 has a base 119 and one or more flanges 111. The base 119, which has an aperture 116, can have a convex shape. For example, the base 119 can curve upward in a region near the outer edge 112 relative to a region surrounding the aperture 116. The aperture 116 at the bottom of the base 119 has a tangent plane 113. The flanges 101, which are disposed at the outer edge 112 of the base 119, project angularly upward and away from the base 119, when no tension is applied. For example, the flange 111 can have a tangential plane 114A, which forms an angle α with the plane 113. In a representative, non-limiting embodiment, the angle α is between about 20 degrees and about 70 degrees. In an exemplary embodiment, the angle is about 45 degrees, which can range between about 35 degrees and about 55 degrees.

FIG. 11B shows the cross-section view of the retention element 110 shown in FIG. 11A when an upward tension is applied to a toe strap (not shown) passing through the retention element 110. The tension force can be transferred to the retention element 110 coupled to the toe strap when the retention element 110 is urged against a bottom portion of the sole (not shown). Accordingly, the flanges 111 can expand outwardly toward the plane 113 that is tangent to the base 119 when the flanges 111 are urged against the bottom portion of the sole. Thus, the plane 114B of the expanded flange 111 can be pressed toward the base 119, and the angle α′ between the plane 114B and the base plane 113 is reduced compared to the original angle α. Yet according to an alternative embodiment, the flanges 111 can be made of a rigid material. When the flanges 111 are urged against the bottom portion of the sole, the flanges 111 do not deform and retain its original shape and orientation with respect to the base 119. Since the sole is typically made of foamed rubber material, the flanges 111 can piece into and grip the sole. As the flanges 111, either being made of deformable or rigid material, are pressed against the bottom portion of the sole, the associated toe post can be securely attached to the sole.

FIG. 12A shows a cross-sectional view of the retention element shown in FIG. 6 (along line B-B′) according to an alternative embodiment. As shown, the retention element 120 has a base 129 and one or more flanges 121. The base 129, which has an aperture 126, can have a corrugated shape. For example, the base 129 can have a plurality of ridges and furrows on its upper surface. The aperture 126 at the bottom of the base 129 has a tangent plane 123. The flanges 121, which are disposed at the outer edge 122 of the base 129, project angularly upward and away from the base 129, when no tension is applied. For example, the flange 121 can have a tangential plane 124A, which forms an angle α with the plane 123. In a representative, non-limiting embodiment, the angle α is between about 20 degrees and about 70 degrees. In an exemplary embodiment, the angle is about 45 degrees, which can range between about 35 degrees and about 55 degrees.

FIG. 12B shows the cross-section view of the retention element 120 shown in FIG. 12A when an upward tension is applied to a toe strap (not shown) passing through the retention element 120. The tension force can be transferred to the retention element 120 coupled to the toe strap when the retention element 120 is urged against a bottom portion of the sole (not shown). Accordingly, the flanges 121 can expand outwardly toward the plane 123 that is tangent to the base 129 when the flanges 121 are urged against the bottom portion of the sole. Thus, the plane 124B of the expanded flange 121 can be pressed toward the base 129, and the angle α′ between the plane 124B and the base plane 123 is reduced compared to the original angle α. Yet according to an alternative embodiment, the flanges 121 can be made of a rigid material. When the flanges 121 are urged against the bottom portion of the sole, the flanges 121 do not deform and retain its original shape and orientation with respect to the base 129. Since the sole is typically made of foamed rubber material, the flanges 121 can piece into and grip the sole. As the flanges 121, either being made of deformable or rigid material, are pressed against the bottom portion of the sole, the associated toe post can be securely attached to the sole.

It should be understood that the examples shown in FIGS. 10A-10B, 11A-11B, and 12A-12B are not limiting. The base of the retention element can have other shapes without departing from the principles described above.

FIG. 13 shows another representative, non-limiting embodiment of a retention element 130. As shown, the retention element 130 has a plurality of flanges 131 a, 131 b, 131 c and 131 d, any of which can include one or more barbs 137 a, 137 b, 137 c and 137 d, on a peripheral edge of the respective flange. When the flanges 131 a, 131 b, 131 c and 131 d are urged against the bottom portion of the sole, the barbs on the respective flanges (137 a, 137 b, 137 c and 137 d) can piece into and grip the sole, thus helping to securely attach the associated toe post to the sole.

While each of the retention elements described above has a gap in the base so that the retention element can be assembled over the strap (e.g., by sliding the strap through the gap into the aperture of the retention element), in other embodiments the retention element does not need to have a gap. For example, FIG. 14 shows a retention element 140 having a base 149 and four flanges (141 a, 141 b, 141 c and 141 d) disposed at an outer edge 142 of the base 149 projecting angularly upward and away from the base 149. Similarly, the base 149 can also have an aperture 146. However, the base 149 has no gap extending from the outer edge 142 to the aperture 146.

According to certain embodiments, the retention element 140 can be integrated with the corresponding strap in a unitary structure. For example, FIG. 15 shows a toe post 150 having a plug end 155, a retention element 159, and a thong strap 152, all integrated together to form a unitary structure. To assemble the sandal, the integrated toe post 150 can be inserted from the bottom portion 157 b to the top portion 157 a of the sole 157 via a channel 154. As shown, the top opening 154 a can be wider than the bottom opening 154 b of the channel 154. Channel 154 terminates to a recess 153, which can receive the portion of integrated plug end 155 and the retention element 159. The flanges 151 of the retention element 159 can form an interference fit against an area surrounding the bottom opening 154 b of the channel 154 in the recess 153, so that the toe post 150 can be securely attached to the sole 157. The thong strap 152 can exit the top portion 157 a of the sole 157 and be coupled to the medial and/or lateral straps to form a part of the sandal's upper.

FIG. 16 shows an alternative embodiment. In this example, the toe post 160 has a plug end 165, a plurality of flanges 161, and a thong strap 162, all integrated together to form a unitary structure. Note that in this example, the plurality of flanges 161 are disposed directly on the plug end 165. In other words, the plug end 165 itself functions as the base of a retention element.

To assemble the sandal, the integrated toe post 160 can be inserted from the bottom portion 167 b to the top portion 167 a of the sole 167 via a channel 164. As shown, the top opening 164 a can be wider than the bottom opening 164 b of the channel 164. Channel 164 terminates to a recess 163, which can receive the portion of integrated plug end 165 and the plurality of flanges 161. The flanges 161 can form an interference fit against an area surrounding the bottom opening 164 b of the channel 164 in the recess 163, so that the toe post 156 can be securely attached to the sole 167. The thong strap 162 can exit the top portion 167 a of the sole 167 and be coupled to the medial and/or lateral straps to form a part of the sandal's upper.

Any of the retention elements described herein, or a unitary retention element/plug end, such as plug end 165, can have a variety of shapes, for example, a plate; disc; rectilinear; block, sphere, or other volumetric shape; ellipsoid; cylinder, etc.

Persons skilled in the art will recognize that many modifications and variations are possible in the details, materials, and arrangements of the parts and actions which have been described and illustrated in order to explain the nature of the inventive subject matter, and that such modifications and variations do not depart from the spirit and scope of the teachings and claims contained therein.

All patent and non-patent literature cited herein is hereby incorporated by references in its entirety for all purposes.

As used herein, “and/or” means “and” or “or”, as well as “and” and “or.” Moreover, any and all patent and non-patent literature cited herein is hereby incorporated by references in its entirety for all purposes.

The principles described above in connection with any particular example can be combined with the principles described in connection with any one or more of the other examples. Accordingly, this detailed description shall not be construed in a limiting sense, and following a review of this disclosure, those of ordinary skill in the art will appreciate the wide variety of systems that can be devised using the various concepts described herein. Moreover, those of ordinary skill in the art will appreciate that the exemplary embodiments disclosed herein can be adapted to various configurations without departing from the disclosed principles.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the disclosed innovations. Various modifications to those embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of this disclosure. Thus, the claimed inventions are not intended to be limited to the embodiments shown herein, but are to be accorded the full scope consistent with the language of the claims, wherein reference to an element in the singular, such as by use of the article “a” or “an” is not intended to mean “one and only one” unless specifically so stated, but rather “one or more”.

All structural and functional equivalents to the elements of the various embodiments described throughout the disclosure that are known or later come to be known to those of ordinary skill in the art are intended to be encompassed by the features described and claimed herein. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed as “a means plus function” claim under US patent law, unless the element is expressly recited using the phrase “means for” or “step for”.

The inventors reserve all rights to the subject matter disclosed herein, including the right to claim all that comes within the scope and spirit of the following claims:

The inventor(s) reserves the right to claim, without limitation, at least the following subject matter. 

1. An article of footwear, comprising: a sole having a top portion and a bottom portion; and one or more straps, wherein at least one of the straps extends from the top portion to the bottom portion through a channel in the sole, and the strap has a plug end; and a retention element disposed between the plug end and the bottom portion of the sole, wherein the retention element comprises a base and one or more flanges disposed at an outer edge of the base projecting angularly upward and away from the base.
 2. The article of footwear of claim 1, wherein the channel terminates to a recess at the bottom portion of the sole, and the retention element is configured to engage with the sole by an interference between the flanges and an area surrounding a bottom opening of the channel in the recess when an upward tension is applied to the strap.
 3. The article of footwear of claim 1, wherein the base has a generally planar surface.
 4. The article of footwear of claim 1, wherein the base has an aperture configured to allow the strap to pass through.
 5. The article of footwear of claim 4, wherein the base has a gap extending from the outer edge to the aperture, and the retention element is configured to allow the strap to pass through the gap into the aperture.
 6. The article of footwear of claim 1, wherein the strap is a toe post positioned at a front region of the sole.
 7. The article of footwear of claim 1, wherein the strap is positioned at a medial side or a lateral side of the sole.
 8. The article of footwear of claim 1, wherein the base and any of the flanges form an angle between 20 degrees and 70 degrees.
 9. The article of footwear of claim 8, wherein the angle is about 45 degrees.
 10. The article of footwear of claim 1, wherein the flanges are made of a resiliently deformable material.
 11. The article of footwear of claim 2, wherein the flanges expand outwardly toward a plane that is tangent to the base when the flanges are urged against the area surrounding the bottom opening of the channel.
 12. The article of footwear of claim 1, wherein the flanges are made of a rigid material.
 13. The article of footwear of claim 1, wherein the retention element is integrated with the strap in a unitary structure.
 14. The article of footwear of claim 2, wherein a widest width of the bottom opening of the channel is smaller than a distance between two opposing points on a peripheral edge of flanges.
 15. The article of footwear of claim 1, wherein any of the flanges comprises one or more barbs on a peripheral edge of the flange.
 16. A strap system for a sandal, comprising: a strap passing through a channel across a sole of the sandal, wherein the strap has a plug end; and a retention element disposed between the plug end and a bottom portion of the sole, wherein the retention element comprises a base and one or more flanges disposed at an outer edge of the base projecting angularly upward and away from the base.
 17. The strap system of claim 16, wherein the channel terminates to a recess at the bottom portion of the sole, and the retention element is configured to engage with the sole by an interference between the flanges and an area surrounding a bottom opening of the channel in the recess when an upward tension is applied to the strap.
 18. The strap system of claim 16, wherein the base has a generally planar surface.
 19. The strap system of claim 16, wherein the base has an aperture configured to allow the strap to pass through.
 20. The strap system of claim 19, wherein the base has a gap extending from the outer edge to the aperture, and the retention element is configured to allow the strap to pass through the gap into the aperture.
 21. The strap system of claim 16, wherein the strap is a toe post positioned at a front region of the sole.
 22. The strap system of claim 16, wherein the strap is positioned at a medial side or a lateral side of the sole.
 23. The strap system of claim 16, wherein the base and any of the flanges form an angle between 20 degrees and 70 degrees.
 24. The strap system of claim 23, wherein the angle is about 45 degrees.
 25. The strap system of claim 16, wherein the flanges are made of a resiliently deformable material.
 26. The strap system of claim 17, wherein the flanges expand outwardly toward a plane that is tangent to the base when the flanges are urged against the area surrounding the bottom opening of the channel.
 27. The strap system of claim 16, wherein the flanges are made of a rigid material.
 28. The strap system of claim 16, wherein the retention element is integrated with the strap in a unitary structure.
 29. The strap system of claim 17, wherein a widest width of the bottom opening of the channel is smaller than a distance between two opposing points on a peripheral edge of flanges.
 30. The strap system of claim 16, wherein any of the flanges comprises one or more barbs on a peripheral edge of the flange.
 31. A method of constructing an article of footwear, comprising: preparing a sole having a top portion and a bottom portion; and attaching one or more straps to the sole, wherein at least one of the straps extends from the top portion to the bottom portion through a channel in the sole, wherein the strap has a plug end; and disposing a retention element between the plug end and the bottom portion of the sole, wherein the retention element comprises a base and one or more flanges disposed at an outer edge of the base projecting angularly upward and away from the base.
 32. The method of claim 31, wherein the channel terminates to a recess at the bottom portion of the sole, and the retention element is configured to engage with the sole by an interference between the flanges and an area surrounding a bottom opening of the channel in the recess when an upward tension is applied to the strap.
 33. The method of claim 31, wherein the base has a generally planar surface.
 34. The method of claim 31, wherein the base has an aperture configured to allow the strap to pass through.
 35. The method of claim 34, wherein the base has a gap extending from the outer edge to the aperture, and the retention element is configured to allow the strap to pass through the gap into the aperture.
 36. The method of claim 31, wherein the strap is a toe post positioned at a front region of the sole.
 37. The method of claim 31, wherein the strap is positioned at a medial side or a lateral side of the sole.
 38. The method of claim 31, wherein the base and any of the flanges form an angle between 20 degrees and 70 degrees.
 39. The method of claim 38, wherein the angle is about 45 degrees.
 40. The method of claim 31, wherein the flanges are made of a resiliently deformable material.
 41. The method of claim 40, wherein the flanges expand outwardly toward a plane that is tangent to the base when the flanges are urged against the area surrounding the bottom opening of the channel.
 42. The method of claim 31, wherein the flanges are made of a rigid material.
 43. The method of claim 31, wherein the retention element is integrated with the strap in a unitary structure.
 44. The method of claim 31, wherein a widest width of the bottom opening of the channel is smaller than a distance between two opposing points on a peripheral edge of flanges.
 45. The method of claim 31, wherein any of the flanges comprises one or more barbs on a peripheral edge of the flange. 